The class of polymers of carbon monoxide and olefin(s) has been known for a number of years. Brubaker, U.S. Pat. No. 2,495,286, produced such polymers of relatively low carbon monoxide content in the presence of free radical catalysts, e.g., peroxy compounds. U.K. No. 1,081,304 produced similar polymers of higher carbon monoxide content in the presence of alkylphosphine complexes of palladium salts as catalyst. Nozaki extended this process through the use of arylphosphine complexes of palladium salts and certain inert solvents, e.g., U.S. Pat. No. 3,694,412.
More recently, the class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon, which polymers are also known as polyketones or polyketone polymers, has become of greater interest because of the greater availability of the polymers. More recent processes for the production of such polyketones are illustrated by published European Patent Applications Nos. 0,121,965 and 0,181,014 and copending U.S. patent application Ser. No. 930,468, filed Nov. 14, 1986. The process generally involves the use of a catalyst composition formed from a compound of the Group VIII metals palladium, cobalt or nickel, the anion of a non-hydrohalogenic acid having a pKa less than about 6, frequently less than about 2, and a bidentate ligand of phosphorus, arsenic or antimony. Although the scope of the polymerization process is extensive, it is frequently preferred to use a catalyst composition formed from palladium acetate, the anion of trifluoroacetic acid or p-toluenesulfonic acid and a bidentate phosphorus ligand selected from 1,3-bis(diphenylphosphino)propane and 1,3-bis[di(2-alkoxyphenyl)-phosphino]propane.
The polyketone polymers are represented by the formula --CO--A-- wherein A is the moiety of ethylenically unsaturated hydrocarbon polymerized through the ethylenic unsaturation. For example, when the ethylenically unsaturated hydrocarbon is ethylene, the polymer is represented by the formula --CO--CH.sub.2 --CH.sub.2 --.
The polymerization process is typically conducted in a liquid phase in a diluent in which the catalyst composition components are soluble but in which the polymer product is insoluble. The insoluble polymer will typically contain residues of the catalyst that could interfere with subsequent processing of the polymer, particularly melt processing at elevated temperature. It would be of advantage to provide a method of recovering polymer having reduced quantities of catalyst residue and therefore higher polymer purity.